This invention relates to methods for manufacturing vehicle frame components. More specifically, this invention relates to an improved method for manufacturing a side rail for use in a vehicle frame assembly.
Most land vehicles in common use, such as cars and trucks, use a frame that serves as a platform upon which the remainder of the vehicle is built. Many vehicle frame structures are known in the art. Most known structures are formed from a number of individual metallic components that are permanently joined together. For example, a typical perimeter vehicle frame assembly is composed of a pair of longitudinally extending side rails that are joined together at the front and rear by a pair of transversely extending cross members. Additional connections between the side rails are made at intermediate locations using one or more intermediate or auxiliary cross members. The cross members not only connect the two side rails together, but also provide desirable lateral and torsional rigidity to the vehicle frame assembly.
In some vehicle frame assemblies, the side rails and cross members are formed from open channel structural members, i.e. structural members that have a non-continuous cross sectional shape. A typical open channel structural member is C-shaped in cross section. In a frame assembly, such a structural member is positioned so that the open legs of the "C", called the upper and lower flanges, are essentially parallel to the ground. The upper and lower flanges are connected to each other by a web (the back of the "C"). The web forms a plane that is perpendicular to the ground. In an open channel structural member, the edges of the flanges define a plane that is parallel to the plane defined by the web.
For certain vehicle applications, it is desirable to deform a portion of the side rail to provide a deformation or kick-up portion in one of the flanges. This kick-up portion provides clearance for vehicle components, such as a rear axle and drive train assembly. It is often desirable that the side rail have a kick-up in a portion of the lower flange only and the upper flange remain straight.
To manufacture a C-shaped open channel structural member, an elongated flat steel stock is stamped to the desired shape. For example, it is known to form a C-shaped member as a structural component for vehicle frames including an upper flange that extends horizontally the length of the side rail, and a lower flange that extends horizontally the length of the rail, except for the kick-up portion. The edges of these flanges form a plane that is parallel to the plane defined by the web.
In order to stamp C-shaped members of the required length, particularly for use in sport utility vehicles, vans, and trucks, relatively long dies that extend the total length of the side rail are required. Unfortunately, a large industrial press must be used to handle such long dies. And the formation of side rails of different configurations for different vehicles requires multiple dies. Although the technology of stamping using large dies and presses is well known, the scale makes the overall process expensive. Thus, it would be desirable to provide a method of manufacturing C-shaped structural members for use as side rails in vehicle frames that is less expensive than a large scale stamping operation. It would also be desirable to provide a method of manufacturing C-shaped structural members for use as side rails that is easily scalable to different vehicle sizes.